Make an upside down telescope

Look up to the night sky

Astronomers use telescopes to see the stars. You can build your
own telescope to find out how they work.

What you need:

Scissors

Pencil

Corrugated card - 24 inches in length

Strong glue

2 magnifying glasses - same size

Marker pens or felt tips (optional)

How to:

These step-by-step videos will show you how to make your own
telescope.

Wrap the corrugated paper around the edge of the magnifying
glass. Draw a line on the corrugated paper to mark the diameter of
the magnifying glass.

Measure an inch and a half from your first mark and make a
second mark. Cut straight along the length of the corrugated paper
from this mark.

Cut the piece of corrugated paper in half widthways.

Wrap the first piece of corrugated card around a magnifying
glass and glue securely.

Glue the edges of the corrugated card together.

Repeat for the second piece of corrugated card and magnifying
glass. Make the second tube of corrugated card slightly wider than
the first tube, so the first tube can move in and out of the second
tube.

Put the first tube inside the second tube. You should have a
magnifying glass at either end.

Decorate your telescope with marker pens or felt tips.

If you want, you can put markings on the telescope to show where
each distance comes into focus. Put an object a foot away from the
telescope. Move the inner tube out and in until the object comes
into focus. Make a mark around the inner tube where it meets
the outer tube.

This line shows you that when an object is a foot away it will
come into focus when the two tubes are in this position. Repeat for
objects at different distances from the telescope.

What's happening?

All the images you see in the telescope are upside down, because
you're using two magnifying glasses. This doesn't matter very much
to astronomers. In space there is no up or down!

Your telescope might not be powerful enough to view the stars
clearly. If you'd like to build a more powerful telescope to look
at the stars, have a look online. You can buy kits to help you
build your own telescope.

Curriculum information

Summary

Ancient Greek and Arabic astronomers did it. Children can look for patterns in the stars and there are handy web links to help them identify constellations. The activity also shows how to make a simple telescope using magnifying glass lenses.

Curriculum key words

Other web links

• Earth, solar system and beyond• Observing and recording• Light and lenses